This is a 48 week, open label, randomized, multicenter trial which will evaluate the safety and efficacy of combination regimens of ritonavir and saquinavir in HIV-infected men & women. Patients will be closely monitored for adverse events laboratory abnormalities, drug tolerability & HIV RNA levels. The pharmacokinetics of this combination will be measured in a subset of patients on day 28 The development of viral resistance will be monitored for inpatients who experience virologic failure while receiving two protease inhibitors.